Melanocytic Slide ClubCase 202

Dr Richard A. Carr

M73. Pigmented lesion L cheek ?melanoma. Nov 2009

Results (N=28)• BENIGN 0

• MALIGNANT 28– LMM 19– SSMM 1– Nodular 1– Min. Dev. 1– Spitzoid 1– Unclass. 2

Results (N=28)• Clark

– I 0– II 3– III 10– IV 5– V 1

• Breslow– Median (range): 0.8 (0.3 to 1.7)

• Growth Phase: R = 1; V = 21

• Regression: Y = 0; N = 20

• Mitoses: Absent = 8; Low = 11

“Difficult definite LMM, ?deep dermal component”

“Melanoma arising in LM mitoses 2/mm²

“Favour LMM over unclassifiable”

“Pigment synthesising melanoma / animal type - cell type similar to that described in pigmented epithelioid melanocytoma.”

“Atypical proliferation of epithelioid cells in the epidermis with similar cells in the dermis. “

Expert Comments

Other Section (not circulated)

At 2 months: Wider local excision. Sampled in 2 TS. No Tumour

At 6 Months: Revision of Scar (keloidal)

At 18 Months: Local Recurrences x 3

Dermal Pigmented Epithelioid Cell Component (Dermal Nodule)

Ball and Gorlitz 1994 Jam Acad Dermatol: 73 cases

• Clinical: 6.2mm mean dia. with central 1-5mm dark brown or black macule or papule of recent onset

• Ordinary acquired or congenital naevus• Central focus or foci of large epithelioid melanocytes in

variably sized nodular aggregates• Heavily pigmented• Cytologically bland or atypical• Occupying 5 to 80% of naevus• Associated melanophages• Often transition of surrounding naevus• Differential Diagnosis: Melanoma, Combined naevus

Melanocytic naevus with phenotypic heterogeneity (Atypical Dermal Nodule)

v’s Melanoma• Symmetrical v’s asymmetrical• Size: often <6mm v’s often >1cm• Lateral borders: Sharply v’s poorly defined• Focus: present well demarcated v’s variable• Atypia: absent or mild v’s moderate to severe• Mitoses: Absent or minimal v’s frequent• Lymphcytic reaction: Uncommon v’s frequent

Learning Points

• Beware of the epithelioid / pigmented clone in sun-damaged skin of the elderly!!

• Not all malignant lesions have a prominent host inflammatory reaction

• Mitotic figures may be sparse!